Electromagnetically-operated horn.



B. AMES.

ELECTROMAGNETICALLY OPERATED HORN.

APPLICATION FILED EB.1,19I5.

Patented July 3, 1917.

UNITED STATES PATENT OFFICE.

BUTLER AMES, oF' LOWELL, inussncnusnfrrs.\y

ELECTBOMAGNEIICALLY-OPEBATED HORN.

Specification of Letters Patent.

Application filed February 1`, 1915. Serial No. 5,389.

To all whom 'it may concern: n

Be it known that I, BUTLER AMES, citizen of the United States, residing at Lowell, in the county of Middlesex and State of Massachusetts, have invented certain new and useful Improvements in Electromagnetically- Operated Horns, of which the following 1s aspecifieation, reference being had therein tothe accompanying drawings.

My invention relates to electro-magnetically operated percussion diaphragm horns, and is embodied in means for adjusting the electro-magnet and its vibrator in relation -to each other and to the button of the diaphragm, so that the vibrations of the diaphragm and those of the vibrator armature volves at a speed changing from 200 to' 2000` revolutions perminute, and the generator has a frequency of lfor each revolution of its armature.

Itag'ytility will' become still more evident when one considers that electro-magnets and vibrators, su posed to be alike, do as a matter ofv fact iier from each other in magnetical and Velectrical efficiency; and that, while a horn, electro-magnet and vibrator might be fixed in vroper relations successfully to operate with an alternator generating acurrent having certain frequencies and voltage, yet it would be valueless were it used without change, in connectionwith a current different in frequency and voltage, for the vibrations of the diaphragm and the vibrator would not be' in time and would not be in op osite directions. y

In fine, a horn embodying my invention may be adapted for use in automobiles having diEerent engines, generators, and alterole of my invention and the be@ 1n` e now,

nating currents having different frequencies and voltages.

In the drawings illustrating the rinciknown to me of embodying the same` in operative structure,

Figure 1 'shows my invention in elevation, part of the associated horn being broken away for clcarness.

Fig. 2 is -a plan of the housing, showing ratchet and holes for retaining parts in ad` justment.; the vibrating unit having been removed.

Fig. 3 is a plan of the vibrating unit mounted in the housing.V

Patented July 3, 1917.

The bell A, flange B. diaphragm (l, but- ,i n

ton I), packing E, washers F, housing Gare old, so are theelectro-magnet H, core I and vibrator J.

The vibrator support 1 is secured to they base 2 of the core, and extends parallel with the magnets H until it yreaches about the' plane containing thepoles of the magnet, Where it bends at right angles and extends outwardly -a short distance where it is" back upon itself and ends with` a substantially parallel. surface 3 `upon vwhich is mounted the vibrator J secured thereto by` screws 4; the position of the vibrator being varied and determined by an .adjustingy screw opposite aV hole 5 in thefhousing (irv and mountcdfin the support and controlv ling the distance between the vibrator and the poles of the magnet.

Axially fixed to the core I is a threaded adjustingrrest 6 which is in screwengagement with an adjustin head 7-located in the longitudinal axis o the horn and housing, where it is retained by a shoulder 8..

contacting the outside of the housing, vand by a headed portion 9 within thehousing,

which confines by-means of a washer 10, a flatspring ratchet 11 close to the bottom of the housing; a series of ratchet holes 12, Figs. 2 and 3, are arranged in the bottom of the' housing, in a circle `having said axis as a center, and designed to be engaged by projections 13 in the adjacent face of the ratchet spring 11,; the adjusting head 7, washer l0 and ratchetl 11 being fixed together and rotatable in relation vto the housing.

To revent rotation of the vibratin unit,

two pms 14, one on each side of the vi rater rest, are fixed in the flanged portion of the housing.

To use my invention, the coils of the electro-magnet arev assumed to be connected with a generator of an alternating current that may be subjected to various loads such` as electric lighting, etc.; the generator' being driven as by an internal combustion engine. The vibrator J is caused to press against the button D of the, diaphragm C. This is brought about by turning the head 7 which causes the. threaded rest 6 to move forward the vibrator unit, confined between the guide pins 14, and thus prevented from rotating.

y'lhis pressure exerted b v the bent vibrator against the blitton D of the diaphragm. causes the latter to be. moved into a position slightly ahead ot' that it would occupy were it at rest and not engaged hv the. vibi'ator. The generator being in operation. the current is nevt allowed to energize the magnet Il; tliefrequenc)v of vibrations. and the sti ti'- ne y ot the vibrator spring and diaphragm causing the successive hammer blows'ot the vibrator upon. the button ot' the diaphragm to follow with a rapidit)v and force that will prevent the diaphragm from returning to the plane it would occupi' were it at rest. The vibrations of the vvibrator and diaphragm being synchronous and opposite. the desired quality of sound results.

Now should tln` voltage o'l' the alternating current be reduced. as lrv the usc ot' some ol` the current for electric lighting purposes,

the amplitude ot vibration ot the vibrator might be so reduced, due to the diminutionot' the.- strength of the magnetic lield of the electro-magnet. that the percussion ol the hammer vibrator. of the diaphragm would result in an injurious loss of sound. ln such an event the adjusting screw 5 would. through the opening 5a in the housing (l.

be so turned as to draw the vibrator nearer` to the poles ot' the magnet. while the whole vibrating unit would be moved torward by operating the adjusting head 7. to restore the original tension between the vibrator and the diaphragm. as already explained.

lt' these adjustments ai'e rightthe vibrator will strike a hannneimbloiv upon-the diaphragm with the saine `force as before. for the frequency remains the same. and the pull ot the magnet is not changed. for although the magnetizii'ig current is less in "strength and hence there is less strength ot' magnetic field. yet. :is the vibrator has been movednearer the poles oi' the"maguet. it is vphragm and vibrator.

Tt is to be noted that in moving the adjusting head 7. theI resistance of the projeetions 13 oi the ratchet 11 to being moved out of the ratchet holes 1Q, has to be overcome; and that this `resistance is suliicient to hohl the ratchet and hence the vibrating unit in any particular adjustment.

Desiring to protett my invention. in the broadest manner legally possible, i

'hat I claim is:

ln an electro-niagnetically operated percussion horn having :1.,combined housing and l'lange. a. diaphragm. an elerlro-magnel. a vibrator. a base fbi' the electro-magnet. an adjustable head rotznably mounted in the housing. and in .theftlongitudinal axis ot the horn` said headl bilirig manually operated outside ol said housing. a threaded adjustingrest fixed to snijd base of said magnet.. and rotatabliv mounted in. and in relation to. Isaid head. and in` Isaid longitudinal axis,

a :spring ratchet lixed to said head and hai'- 

